Petraeus resigned from his post as director of the CIA earlier this month after his affair with biographer Paula Broadwell were revealed. He had previously commanded U.S. forces in Afghanistan.

MailOnline said the letter was sent to Shelton, a friend of three decades, on Nov. 20, 11 days after Petraeus stepped down from his CIA role.

Shelton blamed Broadwell for the affair in an interview with the website, saying Petraeus “was the innocent one when it came to relationships.”

“Paula was more savvy than Dave about the nature of the things that they got involved with,” Shelton said.

“She was a beautiful woman, very intelligent and if David would say something she would know what he was talking about. They were both West Point Academy graduates, that’s what put them together. She had a lot of the qualities that he had.

“She’s also a savvy woman. She’s not a kid. In a lot of ways I think she knows more about the world than Dave — I’m talking about sex.

“I don’t think Dave ever thought about that too much, he only thought about the Army and gave it everything he had.”

Disgraced CIA chief David Petraeus admitted he 'screwed up royally' in a letter he sent to a friend following the revelation of his affair with his biographer.
I paid the price (appropriately) and I sought to do the right thing at the end of the day, Petraues said in the...